#define _CRT_SECURE_NO_WARNINGS  1
#include<stdio.h>

int trailingZeroes(int n)
{
    int count = 0;
    while (n > 0)
    {
        n /= 5;
        count += n;
    }

    return count;
}


#include<stdio.h>
int main()
{
    float a = 0;
    int b = 0;
    scanf("%f", &a);
    b = a + 0.5;
    printf("%d", b);
    return 0;
}


int main()
{
    trailingZeroes(30);
}